Journey’s End

The Galileo spacecraft begins to heat and disintegrate as it plunges into the atmosphere of Jupiter in this artist's concept. The entry ended an eight-year reconnaissance of Jupiter on September 21, 2003. Although hampered by the loss of its main radio antenna, the craft transmitted thousands of pictures of Jupiter and its moons, along with data on their composition, Jupiter's magnetic field and radiation belts, and much more. Galileo was intentionally targeted at Jupiter to prevent the dying craft from accidentally hitting the moon Europa, which could have a subsurface ocean of liquid water, and contaminating it with terrestrial bacteria. [NASA/JPL]

After eight years and 35 looping orbits around Jupiter, the Galileo spacecraft was worn out. Its cameras had been destroyed by radiation, its tape recorder was cranky, and it was just about out of fuel. To eliminate any risk that it might crash into one of Jupiter’s icy moons and contaminate it with Earthly bacteria, engineers gave the craft one last command. They told it to slam into Jupiter, where it would burn up in the planet’s thick atmosphere. It did so on September 21st, 2003.

Galileo was a good-news/bad-news type of mission. Its launch was delayed, and its path to Jupiter lengthened, by the loss of space shuttle Challenger. The delays created mechanical problems that kept the craft’s main radio antenna from opening, severely limiting the amount of data it could transmit to Earth.

On the “good-news” side, Galileo became the first spacecraft to fly past an asteroid, and it discovered the first asteroid moon. And after it arrived at Jupiter, in 1995, it dropped a probe into the planet’s atmosphere.

After that, Galileo conducted extensive studies of Jupiter and its moons. It found evidence that oceans of liquid water are hidden beneath the icy crusts of three moons. It measured the composition of the Jovian clouds, and mapped the structure of the planet’s magnetic field.

Despite its problems, Galileo provided the most extensive view yet of the solar system’s largest planet — a mission of exploration that ended 10 years ago today.

Script by Damond Benningfield, Copyright 2013

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